Flame retardant polystyrenic resin composition

ABSTRACT

Flame retardant resin composition comprising (a) an SPS, (b) a thermoplastic resin having a reactive polar group, (c) a compatibilizing agent having compatibility with the component (a) and a polar group capable of reacting with the component (b), (d) a flame retardant and (e) a flame retardant auxiliary, a weight ratio of the component (a)/the component (b) being less than 1.5, the amount of the component (c) being in the range of 0.5 to 10% by weight with respect to 100% by weight of the total of the components (a), (b) and (c), the amount of the component (d) being 10 parts by weight or more and the amount of the component (e) being 3 parts by weight or more with respect to 100 parts by weight of the total of the components (a), (b) and (c).

TECHNICAL FIELD

The present invention relates to a flame retardant resin composition,and more specifically, it relates to a syndiotactic polystyrenic resincomposition having an excellent stiffness, heat resistance, impactresistance and water resistance as well as a high flame retardancy whichcan suitably be used as industrial materials such as electric andelectronic materials, industrial structure materials, automobile parts,appliance parts and mechanical parts.

BACKGROUND ART

A styrenic polymer (hereinafter abbreviated to “SPS” sometimes) having asyndiotactic configuration is excellent in heat resistance, chemicalresistance, water resistance, acid resistance and alkali resistance, butit is poor in impact resistance. For this reason, the application rangeof the styrenic polymer as a material has heretofore been limited. Onthe other hand, a polymer such as a polyamide having a polar group isexcellent in moldability and heat resistance, but it is hygroscopic.When the polyamide absorbs water, the physical properties of thepolyamide change, and they also noticeably deteriorate due to thepresence of an acid or an alkali. Accordingly, it has been desired toovercome such drawbacks.

In order to solve these problems, the formation of an alloy of the SPSand the polyamide has been suggested (Japanese Patent ApplicationLaid-open No. 25795/1987). However, the alloy of the SPS and thepolyamide is poor in flame retardancy, and therefore it cannot be usedas a material which requires the flame retardancy. In recent years, theflame retardancy has been required in many fields, and the developmentof the flame retardant alloy has been desired. However, in the case thata flame retardant is added to the alloy comprising the SPS and thepolyamide alone, it cannot be achieved to impart the flame retardancy tothe alloy, keeping up mechanical properties such as toughness.

Under such circumstances, the present invention has been intended, andan object of the present invention is to provide a resin compositionmaintaining excellent characteristics of the SPS and having a high flameretardancy.

DISCLOSURE OF THE INVENTION

The present inventors have intensively researched, and as a result, ithas been found that the above-mentioned object can be achieved by acomposition obtained by adding a flame retardant to a resin compositioncomprising an SPS, a thermoplastic resin having a reactive polar groupand a specific compatibilizing agent in a predetermined ratio, or acomposition obtained by further blending a specific rubbery elastomerand/or a specific core shell type particulate elastomer with theabove-mentioned composition. The present invention has been completed onthe basis of such a knowledge.

That is to say, the first aspect of the present invention is directed toa flame retardant resin composition which comprises (a) a styrenicpolymer having a syndiotactic configuration, (b) a thermoplastic resinhaving a reactive polar group, preferably a polyamide, (c) acompatibilizing agent having compatibility with the component (a) and apolar group capable of reacting with the component (b), (d) a flameretardant and (e) a flame retardant auxiliary, a weight ratio of thecomponent (a)/the component (b) being less than 1.5, the amount of thecomponent (c) being in the range of 0.5 to 10% by weight with respect to100% by weight of the total of the components (a), (b) and (c), theamount of the component (d) being 10 parts by weight or more and theamount of the component (e) being 3 parts by weight or more with respectto 100 parts by weight of the total of the components (a), (b) and (c).

The second aspect of the present invention is directed to a flameretardant resin composition which comprises the above-mentioned flameretardant resin composition, (f) a rubbery elastomer having a polargroup capable of reacting with the component (b) and a portioncompatible with the component (a) and/or (g) a core shell typeparticulate elastomer having a siloxane.

The third aspect of the present invention is directed to a flameretardant resin composition which comprises the above-mentioned flameretardant resin composition comprising the components (a), (b), (c),(d), (e), (f) and (g), and (h) an inorganic filler.

BEST MODE FOR CARRYING OUT THE INVENTION

A resin composition of the present invention, as described above,comprises (a) a styrenic polymer having a syndiotactic configuration,(b) a thermoplastic resin having a reactive polar group, (c) acompatibilizing agent having compatibility with the component (a) and apolar group capable of reacting with the component (b), (d) a flameretardant and (e) a flame retardant auxiliary.

In the styrenic polymer having the syndiotactic configuration which canbe used as the component (a), the syndiotactic configuration means thatits stereochemical structure has a syndiotactic configuration, i.e., asteric structure in which phenyl groups and substituted phenyl groupswhich are side chains are located alternately in opposite directions ona main chain comprising carbon—carbon bonds. Its tacticity can bequantitatively determined by a nuclear magnetic resonance method usingan isotopic carbon (a ¹³C—NMR method). The tacticity which can bedetermined by the ¹³C—NMR method can be called as follows in accordancewith the number of existing plural continuous constitutional units. Forexample, in the case that the continuous units are two, the tacticity iscalled a diad; in the case that the continuous units are three, it iscalled a triad; and in the case that the continuous units are five, itis called a pentad. The styrenic polymer having the syndiotacticconfiguration referred to in the present invention is polystyrene, apoly(alkylstyrene), a poly(halogenated styrene), a poly(halogenatedalkylstyrene), a poly(alkoxystyrene), a poly(vinyl benzoate), ahydrogenated polymer thereof, a mixture thereof or a copolymer mainlycomprising any of the above-mentioned polymers in which the content ofthe syndiotacticity is preferably 75% or more, more preferably 85% ormore in terms of a racemic diad, or it is preferably 30% or more, morepreferably 50% or more in terms of a racemic pentad. Here, examples ofthe poly(alkylstyrene) include poly(methylstyrene), poly(ethylstyrene),poly(isopropylstyrene), poly(tert-butylstyrene), poly(phenylstyrene),poly(vinylnaphthalene) and poly(vinylstyrene). Examples of thepoly(halogenated styrene) include poly(chlorostyrene),poly(bromostyrene) and poly(fluorostyrene). An example of thepoly(halogenated alkylstyrene) is poly(chloromethylstyrene), andexamples of the poly(alkoxystyrene) include poly(methoxystyrene) andpoly(ethoxystyrene).

Above all, examples of the particularly preferable styrenic polymersinclude polystyrene, poly(p-methylstyrene), poly(m-methylstyrene),poly(p-tert-butylstyrene), poly(p-chlorostyrene), poly(m-chlorostyrene),poly(p-fluorostyrene), hydrogenated polystyrenes and copolymers havingthese constitutional units.

These styrenic polymers can be used singly or in a combination of two ormore thereof.

No particular restriction is put on the molecular weight of thisstyrenic polymer, but its weight-average molecular weight is preferably10000 or more, more preferably 50000 or more. In addition, the width ofa molecular weight distribution is not limited, either, and the styrenicpolymers having various molecular weight distributions are applicable.If the weight-average molecular weight is less than 10000, thermalproperties and dynamic properties of an obtained composition or a moldedarticle unpreferably deteriorate sometimes.

The styrenic polymer having the syndiotactic configuration can beprepared by, for example, polymerizing a styrenic monomer (whichcorresponds to the above-mentioned styrenic polymer) in the presence ofa catalyst comprising a condensed product of a titanium compound, waterand a trialkylaluminum in an inert hydrocarbon solvent or by the use ofno solvent (Japanese Patent Application Laid-open No. 187708/1987).Furthermore, the poly(halogenated alkylstyrene) can be obtained by amethod described in Japanese Patent Application Laid-open No.46912/1989, and the hydrogenated polystyrene can be obtained by a methoddescribed in Japanese Patent Application Laid-open No. 178505/1989.

In the resin composition of the present invention, as the component (a),there can be used a modified SPS having a polar group capable ofreacting with the component (b) which will be described hereinafter.This modified SPS can be obtained by modifying the SPS as the component(a) with a modifier. However, this preparation method of the modifiedSPS is not limited, and any other method can be used, so far as it issuitable for the object of the present invention.

No particular restriction is put on the kind of SPS to be modified, andthe polymers mentioned above as the component (a) can be used, but acopolymer of styrene and a substituted styrene is particularlypreferable from the viewpoint of the compatibility with anothercomponent. A composition ratio of the copolymer is not particularlyrestrictive, but the content of the substituted styrene is preferably inthe range of 3 to 50 mol %. If this content is less than 3 mol %, themodification is difficult, and if it is more than 50 mol %, thecompatibility with another component unpreferably deteriorates. Examplesof the particularly preferable substituted styrene include alkylstyrenessuch as methylstyrene, ethylstyrene, isopropylstyrene, tert-butylstyreneand vinylstyrene, halogenated styrenes such as chlorostyrene,bromostyrene and fluorostyrene, a halogenated alkylstyrene such aschloromethylstyrene, and alkoxystyrenes such as methoxystyrene andethoxystyrene. These substituted styrenes can be used singly or in acombination of two or more thereof.

If the amount of the substituted styrene is 5% by weight or less basedon the weight of the SPS, the polymer having an atactic structure isalso usable. If the amount of the substituted styrene is more than 5% byweight, the heat resistance of the composition unpreferablydeteriorates.

As the modifier which can be used to modify the SPS, there can be used acompound having an ethylenic double bond and a polar group in onemolecule. Examples of such a modifier include maleic anhydride, maleicacid, maleic acid esters, maleimide and its N-substituted compounds,maleates, acrylic acid, acrylic acid esters, acrylic amide, acrylates,methacrylic acid, methacrylic acid esters, methacrylic amide,methacrylates and glycidyl methacrylate. Above all, maleic anhydride andglycidyl methacrylate are preferable. These modifiers can be used singlyor in a combination of two or more thereof.

The modified SPS can be obtained by, for example, reacting the SPS withthe modifier in the presence of a solvent and another resin. Noparticular restriction is put on a method of the modification, and therecan be used a known method, for example, a method which comprisesmelting and kneading these materials at a temperature in the range of150 to 350° C. by the use of a roll mill, a Banbury mixer or an extruderto carry out the reaction, or a method which comprises heating thematerials in a solvent such as benzene, toluene or xylene to carry outthe reaction. Furthermore, in order to facilitate this reaction, it iseffective that a radical generator is allowed to exist in the reactionsystem, and examples of the radical generator include benzoyl peroxide,di-t-butyl peroxide, dicumyl peroxide, t-butyl peroxybenzoate,azobisisobutyronitrile, azobisisovaleronitrile and2,3-diphenyl-2,3-dimethylbutane. A preferable method comprises meltingand kneading the materials in the presence of the radical generator.

Among these modified SPSs, the maleic anhydride-modified SPS isparticularly preferable. Moreover, the modified SPSs may be used singlyor in a combination of two or more thereof.

In the resin composition of the present invention, a thermoplastic resinhaving a reactive polar group can be used as the component (b). Thisthermoplastic resin having the reactive polar group means athermoplastic resin having at least one of polar groups such as acarboxyl group, a hydroxyl group and an amino group. Examples of thethermoplastic resin include polyethylene terephthalate, polypropyleneterephthalate, polybutylene terephthalate, polycyclohexanedimethyleneterephthalate, polyoxyethoxy benzoate, polyethylene naphthalate, widelydefined polyesters such as polyesters obtained by copolymerizing theabove-mentioned polyester-constituting components and other acidcomponents such as isophthalic acid, p-oxybenzoic acid, adipic acid,sebacic acid, glutaric acid, diphenylmethane-dicarboxylic acid and dimeracid and/or glycol components such as hexamethylene glycol, diethyleneglycol, neopentyl glycol, bisphenol A and neopentyl glycol alkyleneoxide adducts, aromatic polyester-polyether block copolymers, aromaticpolyester-polylactone block copolymers and polyallylates, polyamides,polycarbonates, polyolefins such as polar group-modified polyethylenesand polar group-modified polypropylenes, and polyarylene sulfide. Aboveall, polyamides are particularly preferable.

As the polyamides, all of known polyamides are usable. Suitable examplesof the polyamides include 4-polyamide, 6-polyamide, 6,6-polyamide,3,4-polyamide, 4,6-polyamide, 12-polyamide, 11-polyamide,6,10-polyamide, a polyamide obtained from terephthalic acid and4,4′-diaminohexylmethane, a polyamide obtained from azelaic acid, adipicacid and 2,2-bis(p-cyclohexyl)propane, and a polyamide such as adipicacid and m-xylyilenediamine.

The aromatic polyamide resin is a polyamide polymer having, as arepeating constitutional unit, an amide bond in which an aromatic ringis present in a main chain, and it can be suitably selected from thegroup consisting of polymers obtained by reacting aromatic diaminecomponents with dicarboxylic acid components in an ordinary manner andpolymers obtained by reacting diamine components and dicarboxylic acidcomponents each having an aromatic ring in an ordinary manner.

Here, examples of the aromatic diamine components include diamines eachhaving a benzene ring such as 1,4-diaminobenzene, 1,3-diaminobenzene,1,2-diaminobenzene, 2,4-diaminotoluene, 2,3-diaminotoluene,2,5-diaminotoluene, 2,6-diaminotoluene, ortho-, meta- andpara-xylylenediamines, ortho-, meta- andpara-2,2′-diaminodiethylbenzene, 4,4′-diaminobiphenyl,4,4′-diaminodiphenylmethane, 4,4′-diamino diphenyl ether, 4,4′-diaminodiphenylthio ether, 4,4′-diamino diphenyl ketone and4,4′-diaminodiphenyl sulfone. As the aromatic diamine component, theabove-mentioned diamine having the benzene ring may be used singly, oranother aromatic diamine component, for example, a mixture of thearomatic diamine and an aliphatic diamine can also be used, so long asit contains the benzene ring. Needless to say, a mixture of two or morekinds of diamines each having the benzene ring may also be used.

Next, examples of the dicarboxylic acid components include aliphaticdicarboxylic acids such as glutaric acid, adipic acid, pimelic acid,suberic acid, azelaic acid and sebacic acid, aromatic dicarboxylic acidssuch as phthalic acid, isophthalic acid, terephthalic acid andnaphthalene-dicarboxylic acid, and esters and acid chlorides of thesedicarboxylic acids. They may be used singly or in a combination of twoor more thereof.

Furthermore, the aromatic polyamide resin can also be obtained bypolymerizing a ω-amino-ω-carboxyl compound having the aromatic ring, andexamples of the ω-amino-ω-carboxyl compound having the aromatic ringinclude 4-amino-phenylcarboxylmethane,1-(4-aminophenyl)-2-carboxylethane, 3-(4-aminophenyl)-1-carboxylpropaneand p-(3-amino-3′-carboxyl)dipropylbenzene.

The preferable aromatic polyamide resin is a polyamide derived from thediamine having the benzene ring and the aliphatic dicarboxylic acid, andthe more preferable aromatic polyamide resin is a polyamide derived fromxylylenediamine and adipic acid.

This thermoplastic resin having the reactive polar group which is thecomponent (b) may be used singly or in a combination of two or morethereof.

In the resin composition of the present invention, as the component (c),there can be used a compatibilizing agent having compatibility with thecomponent (a) and a polar group capable of reacting with the component(b). This compatibilizing agent can be blended for the purposes ofimproving the compatibility between the components (a) and (b), finelydispersing a domain, and improving surface strength.

The polar group capable of reacting with the component (b) in thecomponent (c) means a functional group capable of reacting with thepolar group which the component (b) has, and typical examples of such afunctional group include acid anhydride groups, carboxylic acid groups,carboxylic acid ester groups, carboxylic acid chloride groups,carboxylic amide groups, carboxylate groups, a sulfonic acid group,sulfonic acid ester groups, sulfonic acid chloride groups, sulfonicamide groups, sulfonate groups, an epoxy group, an amino group, imidegroups and an oxazoline group.

The moiety having the compatibility with the component (a) means amoiety having a skeleton which is compatible with the SPS of thecomponent (a), and typical examples of the moiety having thecompatibility include moieties each having a styrenic chain, a styreniccopolymer segment or a polyphenylene ether segment as a main chain, ablock or a graft chain.

Typical examples of the compatibilizing agent which can be used as thecomponent (c) include styrene-maleic anhydride copolymer (SMA),styrene-glycidyl methacrylate copolymer, terminal carboxylicacid-modified polystyrene, terminal oxazoline-modified polystyrene,terminal amino-modified polystyrene, sulfonated polystyrene, styrenicionomer, styrene-methyl methacrylate graft copolymer, (styrene-glycidylmethacrylate)-methyl methacrylate graft copolymer, acid-modifiedacryl-styrene graft copolymer, (styrene-glycidyl methacrylate)-styrenegraft copolymer, polybutylene terephthalate-polystyrene graft copolymer,modified SPSs such as maleic anhydride-modified SPS, glycidylmethacrylate-modified SPS and amine-modified SPS, and modifiedpolyphenylene ethers such as (styrene-maleic anhydride)-polyphenyleneether graft copolymer, maleic anhydride-modified polyphenylene ether,glycidyl methacrylate-modified polyphenylene ether and amine modifiedpolyphenylene ether. Above all, modified SPSs and modified polyphenyleneethers are particularly preferable.

Examples of the above-mentioned modified SPS include the same modifiedSPSs as mentioned above as the examples of the component (a).Furthermore, the modified polyphenylene ether can be obtained bymodifying a known polyphenylene ether with a modifier, but this manneris not restrictive and another procedure can also be used, so far as itis suitable for the object of the present invention.

The polyphenylene ether is a known compound, and for the sake of themodification of the polyphenylene ether, there can be referred to thespecifications of U.S. Pat. Nos. 3,306,874, 3,306,875, 3,257,357 and3,257,358. The polyphenylene ether can be prepared by an oxidizingcoupling reaction for producing a homopolymer or a copolymer in thepresence of a copper amine complex and one or more phenols eachsubstituted at two or three positions. Here, as the copper aminecomplex, there can be used copper amine complexes derived from primary,secondary and tertiary amines. Suitable examples of the polyphenyleneether include poly(2,3-dimethyl-6-ethyl-1,4-phenylene ether),poly(2-methyl-6-chloromethyl-1,4-phenylene ether),poly(2-methyl-6-hydroxyethyl-1,4-phenylene ether),poly(2-methyl-6-n-butyl-1,4-phenylene ether),poly(2-ethyl-6-isopropyl-1,4-phenylene ether),poly(2-ethyl-6-n-propyl-1,4-phenylene ether),poly(2,3,6-trimethyl-1,4-phenylene ether),poly[2-(4′-methylphenyl)-1,4-phenylene ether),poly(2-bromo-6-phenyl-1,4-phenylene ether),poly(2-methyl-6-phenyl-1,4-phenylene ether), poly(2-phenyl-1,4-phenyleneether), poly(2-chloro-1,4-phenylene ether), poly(2-methyl-1,4-phenyleneether), poly(2-chloro-6-ethyl-1,4-phenylene ether),poly(2-chloro-6-bromo-1,4-phenylene ether),poly-(2,6-di-n-propyl-1,4-phenylene ether),poly(2-methyl-6-isopropyl-1,4-phenylene ether),poly(2-chloro-6-methyl-1,4-phenylene ether),poly(2-methyl-6-ethyl-1,4-phenylene ether),poly(2,6-dibromo-1,4-phenylene ether), poly(2,6-dichloro-1,4-phenyleneether), poly(2,6-diethyl-1,4-phenylene ether) andpoly(2,6-dimethyl-1,4-phenylene ether).

In addition, for example, copolymers can also properly be used which canbe derived from two or more kinds of such phenol compounds as to be usedin the preparation of the above-mentioned homopolymers. Moreover, forexample, there can also be used graft copolymers and block copolymers ofaromatic vinyl compounds such as polystyrene and the above-mentionedpolyphenylene ethers. Above all, poly(2,6-dimethyl-1,4-phenylene ether)is particularly preferable.

As the modifier which can be used to modify the polyphenylene ether,there can be used a compound having an ethylenic double bond and a polargroup in one molecule. Examples of such a modifier include maleicanhydride, maleic acid, maleic acid esters, maleimide and itsN-substituted compounds, maleates, fumaric acid, acrylic acid, acrylicacid esters, acrylic amide, acrylates, methacrylic acid, methacrylicacid esters, methacrylic amide, methacrylates and glycidyl methacrylate.Above all, maleic anhydride, fumaric acid and glycidyl methacrylate arepreferable. These modifiers can be used singly or in a combination oftwo or more thereof.

The modified polyphenylene ether can be obtained by, for example,reacting the polyphenylene ether with the modifier in the presence of asolvent and another resin. No particular restriction is put on a methodof the modification, and there can be used a known method, for example,a method which comprises melting and kneading these materials at atemperature in the range of 150 to 350° C. by the use of a roll mill, aBanbury mixer or an extruder to carry out the reaction, or a methodwhich comprises heating the materials in a solvent such as benzene,toluene or xylene to carry out the reaction. Furthermore, in order tofacilitate this reaction, it is effective that a radical generator isallowed to exist in the reaction system, and examples of the radicalgenerator include benzoyl peroxide, di-t-butyl peroxide, dicumylperoxide, t-butyl peroxybenzoate, azobisisobutyronitrile,azobisisovaleronitrile and 2,3-diphenyl-2,3-dimethylbutane. A preferablemethod comprises melting and kneading the materials in the presence ofthe radical generator.

Among these modified polyphenylene ethers, maleic anhydride-modifiedpolyphenylene ether and fumaric acid-modified polyphenylene ether areparticularly preferable.

In the resin composition of the present invention, the blend ratio ofthe above-mentioned components (a), (b) and (c) can fluctuate in a widerange, but a weight ratio of the component (a)/the component (b) ispreferably 1.5 or less, more preferably in the range of 0.3 to 1.5, mostpreferably 0.5 to 1.2. If the weight ratio of the component (a)/thecomponent (b) is more than 1.5, the component (a) becomes a matrix, sothat mechanical strength deteriorates sometimes. The amount of thecomponent (c) to be blended is preferably in the range of 0.5 to 10% byweight, more preferably 2 to 10% by weight, most preferably 3 to 8% byweight with respect to 100% by weight of the total of the components(a), (b) and (c). If the amount of the component (c) is less than 0.5%by weight, a compatibility effect of the SPS with the polyamide is notexerted, so that the failure of dispersion and the deterioration ofinterfacial strength take place sometimes, and if it is more than 10% byweight, the crystallinity of the SPS is impaired, so that heatresistance deteriorates sometimes.

The resin composition of the present invention further contains a flameretardant as the component (d). No particular restriction is put on thekind of flame retardant, and so the various flame retardants can beused. However, since a kneading and molding temperature is 280° C., itis important that the flame retardant is excellent in heat resistance inthe process. In addition, since the flame retardancy of the whole systemcan be sufficiently improved by making the thermoplastic resin phase ofthe component (b) flame retardant, it is necessary that the flameretardant should locally exist in the thermoplastic resin phase. As theflame retardant, organic halogen-containing flame retardants areparticularly preferable. Examples of the halogen-containing flameretardants include halogenated epoxy compounds, brominated polystyrenessuch as pentabromobenzyl acrylate, halogenated amide compounds,poly(dibromophenylene oxide), polytribromostyrene andpolydibromostyrene, tetrabromobisphenol A, tetrabromophthalic anhydride,hexabromobenzene, tribromophenyl allyl ether, pentabromotoluene,pentabromophenol, tribromophenyl-2,3-dibromo-propyl ether,tris(2,3-dibromopropyl) phosphate, tris(2-chloro-3-bromopropyl)phosphate, octabromodiphenyl ether, decabromodiphenyl ether,octabromobiphenyl, pentachloropentacyclodecane, hexabromocyclododecane,hexachlorobenzene, pentachlorotoluene, hexabromobiphenyl,decabromobiphenyl, tetrabromobutane, decabromodiphenyl ether,hexabromodiphenyl ether, ethylene-bis(tetrabromophthalimide),tetrachlorobisphenol A, tetrabromobisphenol A, tetrachlorobisphenol A,oligomers of halogenated polycarbonates such as oligomers oftetrabromobisphenol A and oligomers of brominated polycarbonates,polychlorostyrene and bis(tribromophenoxy)ethane.

Among these flame retardants, the brominated polystyrenes andpoly(dibromophenylene oxide) are particularly preferable. The brominatedpolystyrenes include polydibromostyrene, polytribromostyrene andcopolymers of these styrene compounds. The brominated polystyrene may beprepared by brominating polystyrene or polymerizing styrene bromide. Thebromine content in each of these flame retardants is preferably 50% ormore.

The amount of the flame retardant to be blended is preferably 10 partsby weight or more, more preferably in the range of 10 to 30 parts byweight, most preferably 15 to 25 parts by weight with respect to 100parts by weight of the total of the components (a), (b) and (c). If theamount of the flame retardant is less than 10 parts by weight, it isdifficult to obtain the flame retardancy as high as an oxygen index of25 or more.

In the case that the brominated polystyrene is used as the flameretardant, a weight ratio of the component (c)/[the component (a)+thecomponent (c)] is preferably 0.06 or more, more preferably in the rangeof 0.06 to 0.2. Furthermore, in the case that poly(dibromophenyleneoxide) is used as the flame retardant, a weight ratio of the component(c)/[the component (a)+the component (c)] is preferably 0.06 or less,more preferably in the range of 0.02 to 0.06. If the ratio deviates fromthis range, the mechanical strength deteriorates sometimes.

In the present invention, it is necessary that a flame retardantauxiliary as the component (e) should be used together with the flameretardant as the component (d), and if either of these agents isomitted, the effect of the present invention cannot be obtained.

Here, no particular restriction is put on the kind of flame retardantauxiliary, and examples of the flame retardant auxiliary includeantimony flame retardant auxiliaries such as antimony trioxide, antimonytetroxide, antimony pentoxide, sodium antimonate, metallic antimony,antimony trichloride, antimony pentachloride, antimony trisulfide andantimony pentasulfide. In addition to these compounds, zinc borate,barium metaborate and zirconium oxide can also be used. Above all,antimony trioxide is particularly preferable.

The amount of the flame retardant auxiliary as the component (e) to beused is preferably 3 parts by weight or more, more preferably in therange of 3 to 10 parts by weight with respect to 100 parts by weight ofthe total of the components (a), (b) and (c). If the amount of the flameretardant auxiliary is less than 3 parts by weight, it is difficult toobtain the flame retardancy as high as an oxygen index of 25 or more.

The resin composition of the present invention comprises theabove-mentioned components (a) to (e) as the essential components, butit may further contain (f) a rubbery elastomer having a polar groupcapable of reacting with the component (b) and a portion compatible withthe component (a) and/or (g) a core shell type particulate elastomerhaving a siloxane.

The rubbery elastomer having the polar group capable of reacting withthe component (b) and the portion compatible with the component (a)which can be used as the component (f) is blended so as to improveimpact resistance, elongation and toughness.

Here, the polar group capable of reacting with the component (b) means afunctional group capable of reacting with a polar group which thecomponent (b) has, and typical examples of the polar group include acidanhydride groups, carboxylic acid groups, carboxylic acid ester groups,carboxylic acid chloride groups, carboxylic amide groups, carboxylategroups, a sulfonic acid group, sulfonic acid ester groups, sulfonic acidchloride groups, sulfonic amide groups, sulfonate groups, an epoxygroup, an amino group, imide groups and an oxazoline group.

Furthermore, the portion compatible with the component (a) means a chainhaving affinity for the SPS or the modified SPS as the component (a),and typical examples of the compatible portion include a main chain, ablock and a graft chain having a styrene chain, a styrene copolymersegment and a polyphenylene ether segment as well as random copolymerrubbers having styrenic monomer units.

Examples of the rubbery elastomer which can be used as the component (f)include styrene-butyl acrylate copolymer rubber, and rubbers obtained bymodifying, with the modifiers having the polar group, styrene-butadieneblock copolymer (SBR), hydrogenated styrene-butadiene block copolymer(SEB), styrene-butadiene-styrene block copolymer (SBS), hydrogenatedstyrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene blockcopolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP),styrene-isoprene-styrene block copolymer (SIS), hydrogenatedstyrene-isoprene-styrene block copolymer (SEPS), styrene-butadienerandom copolymer, hydrogenated styrene-butadiene random copolymer,styrene-ethylene-propylene random copolymer andstyrene-ethylene-butylene random copolymer. Above all, rubbers obtainedby modifying SEB, SEBS, SEP and SEPS are particularly preferable.Typical examples of the rubbery elastomer include maleicanhydride-modified SEBS, maleic anhydride-modified SEPS, epoxy-modifiedSEBS and epoxy-modified SEPS.

These rubbery elastomers as the component (f) may be used singly or in acombination of two or more thereof. The amount of the rubbery elastomerto be blended is preferably in the range of 1 to 30 parts by weight,more preferably 3 to 20 parts by weight with respect to 100 parts byweight of the total of the components (a), (b) and (c). If the amount ofthe rubbery elastomer is less than 1 part by weight, the improvementeffect of the impact resistance cannot sufficiently be exerted, and ifit is more than 30 parts by weight, the elasticity and the heatresistance of the obtained composition deteriorate sometimes.

Furthermore, as the component (g), there can be used a core shell typeparticulate elastomer having a siloxane which is effective for theimpartment of the flame retardancy. As the component (g), methylmethacrylate-alkyl acrylate-dimethylsiloxane copolymer core shell rubber(MASS) is preferable.

The amount of the component (g) to be blended is preferably in the rangeof 1 to 30 parts by weight, more preferably 3 to 20 parts by weight withrespect to 100 parts by weight of the total of the components (a), (b)and (c). If the amount of the component (g) is less than 1 part byweight, the improvement effect of the impact resistance cannotsufficiently be exerted, and if it is more than 30 parts by weight, theelasticity and the heat resistance of the obtained compositiondeteriorate sometimes.

In addition, no particular restriction is put on the particle diameterof the core shell rubber, but it should be selected preferably in therange of 0.05 to 1.5 μm, more preferably 0.1 to 1.0 μm. If the particlediameter of the core shell rubber is less than 0.05 μm, the improvementeffect of the impact resistance is not always sufficient, andconversely, if it is more than 1.5 μm, the dispersion state of the coreshell rubber is poor, so that the improvement of the impact resistancecannot effectively be attained.

Moreover, the resin composition of the present invention can contain aninorganic filler as the component (h). No particular restriction is puton the form of this inorganic filler, and it may take any of a fibrousform, a grainy form or a powdery form. Examples of the fibrous fillerinclude a glass fiber, a carbon fiber and a whisker, and examples of themorphology of the fibrous filler include a cloth, a mat, a cut bundle, ashort fiber, a filament and a whisker. In the case of the cut bundle,its length is preferably in the range of 0.05 to 50 mm, and a fiberdiameter is preferably in the range of 5 to 20 μm. On the other hand,examples of the grainy and the powdery fillers include talc, carbonblack, graphite, titanium dioxide, silica, mica, calcium carbonate,calcium sulfate, barium carbonate, magnesium carbonate, magnesiumsulfate, barium sulfate, calcium oxysulfate, tin oxide, alumina, kaolin,silicon carbide, metallic powder, glass powder, glass flakes and glassbeads. Among these fillers, glass fillers such as glass powder, glassflakes, glass beads, glass filaments, glass fibers, glass rovings andglass mats are particularly preferable.

The above-mentioned filler is preferably subjected to a surfacetreatment with a coupling agent. This coupling agent for use in thesurface treatment is used to improve the adhesive properties of thefiller to the resin, and the coupling agent can optionally be selectedfrom conventional known agents such as the so-called silane couplingagents and titanium coupling agents. Above all, preferable areaminosilanes such as γ-aminopropyltrimethoxysilane,N-β-(aminomethyl)-γ-aminopropyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane andβ-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, epoxy silane andisopropyl-tri(N-amidoethyl, aminoethyl) titanate.

These inorganic fillers may be used singly or in a combination of two ormore thereof. The amount of the filler to be blended is preferably inthe range of 1 to 350 parts by weight, more preferably 5 to 200 parts byweight with respect to 100 parts by weight of the composition. If theamount of the filler is less than 1 part by weight, the blend effect ofthe filler cannot sufficiently be exerted, and if it is more than 350parts by weight, dispersion properties deteriorate, so that the moldinginconveniently becomes difficult.

To the resin composition of the present invention, various additivesand/or another thermoplastic resin can be added, so far as the object ofthe present invention is not impaired. Examples of the additives includean antioxidant, a nucleating agent, a plasticizer, a release agent, aflame retardant, a pigment, carbon black, an antistatic agent.

By the use of the resin composition of the present invention, moldedarticles having excellent physical properties and high flame retardancycan be obtained, irrespective of a molding method. Therefore, the resincomposition of the present invention is suitable for the manufacture ofmolded articles in which the flame retardancy is required, for example,automobile parts such as connectors and cylinder head covers to becarried on automobiles, electric and electronic materials such asconnectors, and the like.

Next, the present invention will be described in more detail, but thescope of the present invention should not be limited at all by theseexamples.

Incidentally, the physical properties of the resin composition wereobtained by the following procedures.

(1) Izod impact strength (notched or unnotched): It was measured inaccordance with JIS K-7110.

(2) Elongation: It was measured in accordance with JIS K-7113.

EXAMPLE 1

20 parts by weight of a brominated polystyrene (hereinafter abbreviatedto “Br—PS”) (trade name PYRO-CHEK 68PB, made by Nissan Fero OrganicChemistry Co., Ltd.) as a flame retardant and 7 parts by weight ofantimony trioxide (trade name ATOX-S, made by The Nihon Mining &Concentrating Co., Ltd.) as a flame retardant auxiliary were added to100 parts by weight of the total of 26.4% by weight of SPS(weight−average molecular weight=400,000), 70% by weight of 6,6-nylon(trade name 2015B, made by Ube Industries, Ltd.) and 3.6% by weight ofmaleic anhydride-modified polyphenylene ether (hereinafter abbreviatedto “MA-PPO”) as a compatibilizing agent, and the mixture was molten,kneaded and then pelletized by a twin screw extruder.

The thus obtained pellets were injection molded to obtain a test piecefor a tensile test, a test piece for an Izod test and a test piece for acombustion test. For the thus obtained test pieces, Izod impactstrength, elongation and an oxygen index were measured, and SEM (surfacescanning electron microscope) observation was then carried out. In theSEM observation, the surface of the test piece was exposed by a cuttingmicrotome, and SPS was only etched to evaluate a matrix and a domain.The results are shown in Table 1.

In this example, SPS (a)/6,6-nylon (b) was 0.37 and MA-PPO (c)/[SPS(a)+MA-PPO (c)] was 0.12, and 6,6-nylon was the matrix as shown in Table1, whereby mechanical properties were improved.

COMPARATIVE EXAMPLE 1

The same procedure as in Example 1 was repeated except that the amountof SPS was 66.4% by weight and that of 6,6-nylon was 30% by weight, andthe results are shown in Table 1.

In this comparative example, SPS (a)/6,6-nylon (b) was 2.2, and MA-PPO(c)/[SPS (a)+MA-PPO (c)] was 0.05.

TABLE 1 Composition and Characteristics Example 1 Comp. Ex. 1 SPS (wt %)26.4 66.4 6,6-nylon (wt %) 70   30   MA-PPO (wt %)  3.6  3.6 FlameRetardant (pts. wt.) 20   20   (Br-PS) Flame Retardant (pts. wt.) 7  7 Auxiliary (Sb₂O₃) Oxygen Index (%) 26.0 24.0 Izod Impact StrengthNotched (KJ/m²)  1.6  1.2 Unnotched (KJ/m²) 28.9 15.7 Elongation (%) 2.6  1.9 Matrix Resin 6,6-nylon SPS

EXAMPLE 2

20 parts by weight of Br—PS (trade name PYRO-CHEK 68PB, made by NissanFero Organic Chemistry Co., Ltd.) as a flame retardant and 7 parts byweight of antimony trioxide (trade name ATOX-S, made by The Nihon Mining& Concentrating Co., Ltd.) as a flame retardant auxiliary were added to100 parts by weight of the total of 44% by weight of SPS (weight−averagemolecular weight=400,000), 50% by weight of 6,6-nylon (trade name 2015B,made by Ube Industries, Ltd.) and 6% by weight of MA-PPO as acompatibilizing agent, followed by the same procedure as in Example 1.The results are shown in Table 2. The dispersion state of the flameretardant was observed by TEM (a transmission electron microscope) tojudge whether the flame retardant was dispersed in a matrix or a domain.

In this example, SPS (a)/6,6-nylon (b) was 0.88, and MA-PPO (c)/[SPS(a)+MA-PPO (c)] was 0.12. As shown in Table 2, in the case of MA-PPO(c)/[SPS (a)+MA-PPO (c)]>0.06, Br—PS was dispersed in the 6,6-nylonmatrix, whereby flame retardancy and mechanical properties were bothimproved.

EXAMPLE 3

20 parts by weight of Br—PS (trade name PYRO-CHEK 68PB, made by NissanFero Organic Chemistry Co., Ltd.) as a flame retardant and 7 parts byweight of antimony trioxide (trade name ATOX-S, made by The Nihon Mining& Concentrating Co., Ltd.) as a flame retardant auxiliary were added to100 parts by weight of the total of 48% by weight of SPS (weight−averagemolecular weight=400,000), 50% by weight of 6,6-nylon (trade name 2015B,made by Ube Industries, Ltd.) and 2% by weight of MA-PPO as acompatibilizing agent, followed by the same procedure as in Example 1.The results are shown in Table 2.

In this example, SPS (a)/6,6-nylon (b) was 0.96, and MA-PPO (c)/[SPS(a)+MA-PPO (c)] was 0.04.

TABLE 2 Composition and Characteristics Example 2 Example 3 SPS (wt %)44   48   6,6-nylon (wt %) 50   50   MA-PPO (wt %) 6  2  Flame Retardant(pts. wt.) 20   20   (Br-PS) Flame Retardant (pts. wt.) 7  7  Auxiliary(Sb₂O₃) Oxygen Index (%) 26.0 25.0 Izod Impact Strength Notched (KJ/m²) 1.8  1.5 Unnotched (KJ/m²) 23.0 21.5 Elongation (%)  2.8  2.8 MatrixResin 6,6-nylon 6,6-nylon Dispersion of 6,6-nylon SPS Flame Retardant

EXAMPLE 4

21 parts by weight of poly(dibromophenylene oxide) (hereinafterabbreviated to “Br-PPO”) (trade name PO64P, made by GLC Co., Ltd.) (abromine amount was regulated in terms of a brominated polystyrene) as aflame retardant was added to 100 parts by weight of the total of 48% byweight of SPS (weight−average molecular weight=400,000), 50% by weightof 6,6-nylon (trade name 2015B, made by Ube Industries, Ltd.) and 2% byweight of MA-PPO as a compatibilizing agent, followed by the sameprocedure as in Example 2. The results are shown in Table 3.

In this example, SPS (a)/6,6-nylon (b) was 0.96, and MA-PPO (c)/[SPS(a)+MA-PPO (c)] was 0.04. As shown in Table 3, in the case of MA-PPO(c)/[SPS (a)+MA-PPO (c)]<0.06, Br-PPO was dispersed in the 6,6-nylonmatrix, whereby flame retardancy and mechanical properties were bothimproved.

EXAMPLE 5

The same procedure as in Example 4 was repeated except that the amountof SPS was 44% by weight and that of MA-PPO was 6% by weight, and theresults are shown in Table 3.

In this example, SPS (a)/6,6-nylon (b) was 0.88, and MA-PPO (c)/[SPS(a)+MA-PPO (c)] was 0.12.

TABLE 3 Composition and Characteristics Example 4 Example 5 SPS (wt %)48   44   6,6-nylon (wt %) 50   50   MA-PPO (wt %) 2  6  Flame Retardant(pts. wt.) 21   21   (Br-PPO) Flame Retardant (pts. wt.) 7  7  Auxiliary(Sb₂O₃) Oxygen Index (%) 26.5 25.5 Izod Impact Strength Notched (KJ/m²) 1.4  1.1 Unnotched (KJ/m²) 21.0 19.4 Elongation (%)  2.7  2.4 MatrixResin 6,6-nylon 6,6-nylon Dispersion of 6,6-nylon SPS Flame Retardant

EXAMPLE 6

20 parts by weight of Br—PS (trade name PYRO-CHEK 68PB, made by NissanFero Organic Chemistry Co., Ltd.) and 7 parts by weight of antimonytrioxide (trade name ATOX-S, made by The Nihon Mining & ConcentratingCo., Ltd.) were added to 100 parts by weight of the total of 34% byweight of SPS (weight−average molecular weight=400,000), 50% by weightof 6,6-nylon (trade name 2015B, made by Ube Industries, Ltd.), 6% byweight of MA-PPO as a compatibilizing agent and 10% by weight of maleicanhydride-modified hydrogenated styrene-butadiene-styrene blockcopolymer (herein after abbreviated to “MA-SEBS” sometimes) (trade nameMX-072, made by Asahi Chemical Industry Co., Ltd.) as a rubberyelastomer of a component (f), followed by the same procedure as inExample 1. The results are shown in Table 4.

EXAMPLE 7

20 parts by weight of Br—PS (trade name PYRO-CHEK 68PB, made by NissanFero Organic Chemistry Co., Ltd.) and 7 parts by weight of antimonytrioxide (trade name ATOX-S, made by The Nihon Mining & ConcentratingCo., Ltd.) were added to 100 parts by weight of the total of 34% byweight of SPS (weight−average molecular weight=400,000), 50% by weightof 6,6-nylon (trade name 2015B, made by Ube Industries, Ltd.), 6% byweight of MA-PPO as a compatibilizing agent and 10% by weight of methylmethacrylate-alkyl acrylate-dimethylsiloxane copolymer as a core shelltype particulate elastomer (made by Mitsubishi Rayon Co., Ltd.)(hereinafter abbreviated to “MASS” sometimes) which was a component (g),followed by the same procedure as in Example 1. The results are shown inTable 4.

EXAMPLE 8

20 parts by weight of Br—PS (trade name PYRO-CHEK 68PB, made by NissanFero Organic Chemistry Co., Ltd.) and 7 parts by weight of antimonytrioxide (trade name ATOX-S, made by The Nihon Mining & ConcentratingCo., Ltd.) were added to 100 parts by weight of the total of 34% byweight of SPS (weight−average molecular weight=400,000), 50% by weightof 6,6-nylon (trade name 2015B, made by Ube Industries, Ltd.), 6% byweight of MA-PPO as a compatibilizing agent, 5% by weight of MA-SEBS and5% by weight of MASS, followed by the same procedure as in Example 1.The results are shown in Table 4.

EXAMPLE 9

The same procedure as in Example 8 was repeated except that the amountof SPS was 38% by weight, that of MA-PPO was 2% by weight, and 21 partsby weight of Br-PPO (trade name PO64P, made by GLC Co., Ltd.) (a bromineamount was regulated in terms of a brominated polystyrene) was used as aflame retardant, and the results are shown in Table 4.

EXAMPLE 10

The same procedure as in Example 6 was repeated except that the amountof SPS was 44% by weight and neither a rubbery elastomer nor aparticulate elastomer was used, and the results are shown in Table 4.

EXAMPLE 11

The same procedure as in Example 9 was repeated except that the amountof SPS was 44% by weight and neither a rubbery elastomer nor aparticulate elastomer was used, and the results are shown in Table 4.

Comparing Examples 6, 7 and 8 with Example 10, and comparing Example 9with Example 11, it is apparent that toughness can be improved,maintaining flame retardancy, by adding the component (f) and/or thecomponent (g).

TABLE 4 Composition and Example Characteristics 6 7 8 9 10 11 SPS (wt %)34 34 34 38 44 44 6,6-nylon (wt %) 50 50 50 50 50 50 MA-PPO (wt %) 6 6 62 6 6 MA-SEBS (wt %) 10 0 5 5 0 0 MASS (wt %) 0 10 5 5 0 0 Flame (pts.wt.) 20 20 20 21 20 21 Retardant Sb₂O₃ (pts. wt.) 7 7 7 7 7 7 OxygenIndex (%) 25.5 33.0 31.0 30.0 26.0 25.5 Izod Impact Strength Notched(KJ/m²) 2.9 2.6 3.5 2.8 1.8 1.1 Unnotched (KJ/m²) 33.9 29.7 38.1 36.123.0 19.4 Elongation (%) 3.4 3.0 3.9 3.5 2.8 2.4

EXAMPLE 12

20 parts by weight of Br—PS (trade name PYRO-CHEK 68PB, made by NissanFero Organic Chemistry Co., Ltd.), 7 parts by weight of antimonytrioxide (trade name ATOX-S, made by The Nihon Mining & ConcentratingCo., Ltd.) and 30 parts by weight of a glass fiber (trade name JA-FT-2A,made by Asahi Fiber Glass Co., Ltd.) were added to 100 parts by weightof the total of 50% by weight of SPS and 50% by weight of 6,6-nylon(trade name 2015B, made by Ube Industries, Ltd.), followed by the sameprocedure as in Example 1. The results are shown in Table 5.

EXAMPLE 13

The same procedure as in Example 4 was repeated except that 30 parts byweight of a glass fiber was added, and the results are shown in Table 5.

EXAMPLE 14

The same procedure as in Example 8 was repeated except that 30 parts byweight of a glass fiber was added, and the results are shown in Table 5.

EXAMPLE 15

The same procedure as in Example 12 was repeated except that any glassfiber was not added, and the results are shown in Table 5.

EXAMPLE 16

The same procedure as in Example 13 was repeated except that any glassfiber was not added, and the results are shown in Table 5.

EXAMPLE 17

The same procedure as in Example 14 was repeated except that any glassfiber was not added, and the results are shown in Table 5.

Comparing Example 12 with Example 15, Example 13 with Example 16, andExample 14 with Example 17, it is apparent that impact strength can beimproved, maintaining flame retardancy, by adding the glass fiber.

TABLE 5 Composition and Example Characteristics 12 13 14 15 16 17 SPS(wt %) 50 44 34 50 44 34 6,6-nylon (wt %) 50 50 50 50 50 50 MA-PPO (wt%) 0 6 6 0 6 6 MA-SEBS (wt %) 0 0 5 0 0 5 MASS (wt %) 0 0 5 0 0 5 Glass(pts. wt.) 30 30 30 0 0 0 Fiber Flame (pts. wt.) 20 20 20 20 20 20Retardant Sb₂O₃ (pts. wt.) 7 7 7 7 7 7 Oxygen Index (%) 26.0 33.0 33.525.5 26.0 31.1 Izod Impact Strength Notched (KJ/m²) 7.2 8.7 9.5 1.2 1.83.5 Unnotched (KJ/m²) 56.0 65.0 77.0 19.4 24.2 33.9

Possibility of Industrial Utilization

As described above, a resin composition of the present invention canexhibit a high flame retardancy, maintaining excellent mechanicalproperties, heat resistance, chemical resistance, water resistance, acidresistance, alkali resistance and the like of a resin composition suchas an SPS/polyamide alloy which comprises an SPS and a thermoplasticresin having a reactive polar group. In the resin composition of thepresent invention, a flame retardant is dispersed in the thermoplasticresin matrix having the reactive polar group, whereby the flameretardancy and the mechanical strength can be improved. The addition ofa specific rubbery elastomer and particulate elastomer can lead to theimprovement of toughness, and the addition of an inorganic filler suchas a glass fiber can also lead to the improvement of physical propertiesand can permit the supply of molded articles having an excellentstiffness.

Therefore, the resin composition of the present invention can suitablybe used as industrial materials such as electric and electronicmaterials, industrial structure materials, automobile parts, applianceparts and mechanical parts.

What is claimed is:
 1. A flame retardant resin composition, whichcomprises: (a) a syndiotactic styrenic polymer having a syndiotacticityof 30% or more in terms of a racemic pentad, and a weight averagemolecular weight of 10000 or more, (b) 6,6-nylon, (c) a maleicanhydride-polyphenylene ether compatibilizing agent, the percent amountsof components (a), (b) and (c) individually based on the sum of thepercentage amounts of (a), (b) and (c), (d) a flame retardant and (e) aflame retardant auxiliary, the weight ratio of component (a)/component(b) being from 0.5 to 1.2, the amount of component (d) being 10-25 partsby weight and the amount of component (e) being 3-10 parts by weighteach with respect to 100 parts by weight of the total of components (a),(b) and (c); and wherein component (d) is poly(dibromophenylene oxide),and the weight ratio of component(c)/(component (a)+component (c)) is0.02-0.06.
 2. The flame retardant resin composition according to claim1, further containing (h) an inorganic filler.